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Interpret · Labs

Electrolytes & renal

Sodium disorders are water disorders, potassium disorders are ECG disorders, and creatinine is a trend, not a number.

The order of operations

  1. 1Osmolality
  2. 2Urine studies
  3. 3Volume status
  4. 4ECG when potassium moves
  5. 5The trend

Sodium 118 in a comfortable patient

core

A 68-year-old on a new antidepressant is referred with a sodium of 118 mmol/L. She is clinically euvolemic and mentating normally.

Weakness with a potassium of 7.1

core

A 58-year-old with diabetes on an ACE inhibitor presents with weakness. The laboratory phones a critical potassium of 7.1 mmol/L.

A creatinine that keeps climbing

core

A 74-year-old admitted with pneumonia is on day 4. You are reviewing the morning bloodwork before rounds.

Thirsty, breathing fast, glucose 32

core

A 19-year-old presents with two days of thirst, vomiting, and deep sighing respirations.

Three days of vomiting

core

A 45-year-old with three days of intractable vomiting from gastric outlet obstruction.